Narrative:

Aircraft X; an erj-175; came in with write-up of engine #2 vibrations up to 4.0. The vibration accelerometers were changed from engine #2 by the line mechanics and it was requested that mechanic Y and I; as mechanic X; perform the vibration engine run and; just in case it failed; we could simply taxi to the hangar from the engine run-up area. We arrived to the run-up area and proceeded with the engine vibration check for engine #2 in reference to general electric (ge) CF34-8e engine subtask 72-00-00. Mechanic Y was seated in left seat operating aircraft and I was in the right seat monitoring and documenting engine #2 vibrations and the amount of time [vibrations occurred] at different settings.after some time it was noticed there was an 'engine exceedence' message on the EICAS for engine #1. We shut down engine #1 and pulled circuit breakers to re-set fadec. Re-started engine #1 and 'engine exceedence' message was gone. We continued with the engine vibration check for engine #2 and brought up engine #1 to match settings to keep in comparison with engine #2. Engine #2 was found within limits. We never got another 'engine exceedence' message so we figured it was good. I signed-off the engine #2 vibration check since it was I who was monitoring the engine-2 and [vibration] times.the following day I spoke to my maintenance manager and was asked about the details of aircraft X and the 'engine exceedence' message on engine #1. After briefly explaining the circumstances to the maintenance manager; he explained to me in reference to the ge manual [that] if an 'engine exceedence' message is found; a boroscope [inspection] is required. We didn't think it would be an issue; since the EICAS message was cleared and didn't return. I realize now; at the very least I should have asked my supervisor about any questions or concerns that might have arose before returning the aircraft to service. Boroscope was completed and found no damage to engine #1.recommend paying better attention to anything and everything that might pop up as an EICAS message and not worry so much about getting the aircraft back in service; to ensure complete 100% compliance; anything not sure about; to double check with immediate supervisors and maintenance manuals.

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Original NASA ASRS Text

Title: Two Mechanics were informed by their Maintenance Manager that required Boroscope Inspections had not been accomplished after they had performed Engine Vibration Run Checks on both GE CF-34 engines for 'ENGINE EXCEEDENCE' EICAS messages. Aircraft; an ERJ-175; was released aircraft for service. It was later grounded and flights canceled.

Narrative: Aircraft X; an ERJ-175; came in with write-up of Engine #2 vibrations up to 4.0. The Vibration Accelerometers were changed from Engine #2 by the line mechanics and it was requested that Mechanic Y and I; as Mechanic X; perform the Vibration Engine Run and; just in case it failed; we could simply taxi to the hangar from the Engine Run-Up area. We arrived to the Run-Up area and proceeded with the Engine Vibration Check for Engine #2 in reference to General Electric (GE) CF34-8e Engine Subtask 72-00-00. Mechanic Y was seated in left seat operating aircraft and I was in the right seat monitoring and documenting Engine #2 vibrations and the amount of time [vibrations occurred] at different settings.After some time it was noticed there was an 'ENGINE EXCEEDENCE' message on the EICAS for Engine #1. We shut down Engine #1 and pulled Circuit Breakers to re-set FADEC. Re-started Engine #1 and 'ENG EXCEEDENCE' message was gone. We continued with the Engine Vibration Check for Engine #2 and brought up Engine #1 to match settings to keep in comparison with Engine #2. Engine #2 was found within limits. We never got another 'ENG Exceedence' message so we figured it was good. I signed-off the ENG #2 Vibration Check since it was I who was monitoring the ENG-2 and [vibration] times.The following day I spoke to my Maintenance Manager and was asked about the details of Aircraft X and the 'ENG Exceedence' message on Engine #1. After briefly explaining the circumstances to the Maintenance Manager; he explained to me in reference to the GE Manual [that] if an 'ENG EXCEEDENCE' message is found; a Boroscope [Inspection] is required. We didn't think it would be an issue; since the EICAS message was cleared and didn't return. I realize now; at the very least I should have asked my Supervisor about any questions or concerns that might have arose before returning the aircraft to service. Boroscope was completed and found no damage to Engine #1.Recommend paying better attention to anything and everything that might pop up as an EICAS message and not worry so much about getting the aircraft back in service; to ensure complete 100% compliance; anything not sure about; to double check with immediate supervisors and Maintenance Manuals.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.